Rotary fluid operated devices employing a stator and a radial vane mounted on an oscillatory shaft may be used as an actuator by admitting pressurized fluid to one side of the vane while releasing fluid from the other side, or they may be used as constant torque resistance devices by regulating the flow of fluid from one side of the vane to the other side of the vane. The device usually has a body with a cylindrical bore and head assemblies at the two ends of the cylindrical bore. The vane on such devices carries a non-metallic sealing material to seal the vane against the inner walls of the bore and the head assemblies to prevent leakage from one side of the vane to the other.
A seal is also required around the ends of the bore, between the heads and the body, to prevent leakage of the liquid between the body and the head assemblies to the outside of the device. If a typical rubberized seal is used between these two parts, the corners of the seals on the vane, at the intersection of the sides of the vane with the outer edge of the vane, will drag along the inner edge of the non-metallic seal around the circumference of the union between the head assemblies and the bore as the vane rotates, and wear away both seals. The seal on the vane will fail at the corners of the vane, and leakage will occur.
The present invention relates to an annular metal seal which seals the body against the head, an example of such a seal can be found in my U.S. Pat. No. 4,495,856. This prior seal requires a flexible plate which is separate from the remainder of the head assembly, and is therefore, more expensive to manufacture than a single piece head assembly.
It would be desirable to create a head member from a single piece of metal which would provide a metal to metal seal where the body sleeve meets the head member around the circumference of the bore.